Modulation by hypergravity of extracellular matrix macromolecules in in vitro human dermal fibroblasts.

In vitro human dermal fibroblasts were submitted to normal gravity (1 g) or to chronic hypergravity (20 g) over a period of 8 days. Changes in organization of extracellular matrix molecules were seen by indirect immunofluorescence. In the fibronectin layer, bundles of fibrils were gathered together leading to a disorganisation of the normal parallel pattern of fibers seen in control cultures.

Effects of hypergravity on the cell shape and on the organization of cytoskeleton and extracelluar matrix molecules of in vitro human dermal fibroblasts.

In vitro human dermal fibroblasts were submitted to normal gravity (1 g) or to chronic hypergravity ranging from 2 to 20 g for 8 days. Changes only appeared above 15 g. The majority of 20 g-subjected cells showed fine filipods in the shape of a star whereas most control cells had rounded shapes and spread by forming lamellipodia.

Influence of a long duration exposure, 69 months, to the space flight factors in Artemia cysts, tobacco and rice seeds.

Three french laboratories have participated in the Free Flyer Biostack experiment. Artemia cysts, tobacco seeds and rice caryopsis and embryos were used. Biological objects in monolayers were dead.

Effects of hypergravity on adherent human cells.

In recent years, accumulating evidence has shown that microgravity or hypergravity may affect cell growth and differentiation. Since it is not easy to carry out researches in space or to simulate weightlessness on earth, we conducted experiments on simulated hypergravity (2 to 15 g) by using a centrifuge (radius: 80 cm; speed motor: 180 rpm). We looked for the effects of chronic hypergravity (7 to 10 days) on cultures of three human cell lines: lung or dermic fibroblasts and lung adenocarcinoma A 549 cells.

Effects of hypergravity on lung carcinoma cells maintained in continuous organotypic culture.

The effects of hypergravity levels ranging from 1 to 15 g were studied on A549 lung adenocarcinoma cell line, cultivated as nodules. This organotypic culture model preserves as closely as possible the cellular structures and differentiation functions of the in vivo situation. Nodules submitted to hypergravity conditions for 27 d did not show any change of cell growth, protein and DNA contents, compared with controls.

Investigations of the effects of cosmic rays on Artemia cysts and tobacco seeds; results of Exobloc II experiment, flown aboard Biocosmos 1887.

Artemia (Brine shrimp) cysts and tobacco seeds, dormant biological material devoid of metabolic activity, were flown aboard the Soviet Biocosmos 1887 in order to investigate the effects of cosmic rays. Artemia cysts and tobacco seeds were used in bulk or in monolayers sandwiched with track detectors. Biological and physical units were located outside and inside the spacecraft.

Space environmental factors affecting responses to radiation at the cellular level.

Previous space experiments suggest a high value for the RBE of cosmic radiation. A possible explanation could be a change in cell radiosensitivity due to a combined effect of radiation and other factors related to the space environment and to the space flight. Results of the EXOBLOC II experiment support this assumption.

Stimulating effect of space flight factors on Artemia cysts: comparison with irradiation by gamma rays.

The Artemia cyst, a gastrula in dormant state, is a very suitable material to investigate the individual effects of HZE cosmic particles. Monolayers of Artemia cysts, sandwiched with nuclear emulsions, flew aboard the Soviet biosatellite Cosmos 1129. The space flight stimulated the developmental capacity expressed by higher percentages of emergence, hatching, and alive nauplii at day 4-5.

Radiation-induced changes in late effects and in developmental capacities of exposed artemia cysts.

Artemia dry cysts from a Californian bisexual strain used in several space experiments were irradiated with 60Co gamma rays. The three cyst populations experimented could be differentiated according to their development and survival rates. The variations observed for both of these criteria were related to the age of the cysts and the selection technique.

Changes in developmental capacity of artemia cyst and chromosomal aberrations in lettuce seeds flown aboard Salyut-7 (Biobloc III experiment).

This paper gives the results of investigations performed on the first container (A) of the Biobloc III experiment, flown aboard the orbital station Salyut 7 for 40 days. The space flight resulted in a decreased developmental capacity of Arterlia cysts, hit or not hit by the HZE particles. No effect was observed in cysts in bulk.

Results on Artemia cysts, lettuce and tobacco seeds in the Biobloc 4 experiment flown aboard the Soviet Biosatellite Cosmos 1129.

Artemia cysts, lettuce and tobacco seeds were flown aboard the Cosmos 1129 for 19 days. A correlative method was used in order to determine the passage of cosmic heavy ions (HZE particles) through the biological test objects. This space flight resulted in a decrease on hatchability, nucleic acid and protein synthesis in hydrated Artemia cysts.

Effects of 645 MeV and 9.2 GeV protons on Artemia eggs.

Developmental capacities of Artemia eggs have been studied after exposure to 645 MeV or 9.2 GeV protons. Effects of proton irradiation were studied in comparison with 60Co gamma ray irradiation, endpoints being emergence, hatching and 4-5 day old live nauplii percentages.

Development capacity of artemia cysts and lettuce seeds flown in Cosmos 936 and directly exposed to cosmic rays.

Developmental capacity of Artemia cysts and chromosomal aberration frequency in lettuce seeds, flown aboard Cosmos 936 have been investigated. Biological objects were located inside or outside the spacecraft. Lettuce seeds were stuck on plastic plates and sandwiched in cellulose sheets in order to discriminate the objects hit by the cosmic heavy ions from the ones not hit.

Radiobiological investigations in Cosmos 782 space flight (Biobloc SF1 experiment).

Several biological objects were flown in Cosmos 782 in order to investigate the effects of HZE cosmic particles and other environmental factors of space. Space flight results in chromosomic aberrations in lettuce seeds, decreased germination rate and increased frequency of abnormalities in tobacco seeds and decreased developmental capacity in Artemia eggs. In lettuce and tobacco seedlings, changes were observed not only in seeds hit by heavy ions but also in nonhit seeds.

Preliminary results of the Biobloc experiment on the Cosmos 782 flight: effects of cosmic rays on brine shrimp eggs and tobacco seeds.

The aim of the Biobloc experiment is to determine the biological effects of cosmic rays. Biobloc is a stack made up of biological layers and physical detectors (nuclear emulsions and plastic). Artemia eggs and tobacco seeds are used by French workers.

[Influence of various physical factors on the developmental capacities of the ovum of Artemia salina].

Artemia salina dry eggs exhibit a great resistance to different physical factors: acceleration and vibration, low temperature, high vacuum and magnetic fields. Vibration test, alone or combined with acceleration test decreases the Artemia salina egg developmental capacity. Nevertheless, the differences are small and much lower than those observed in previous space experiments.